Re-usable carrier structure

ABSTRACT

A re-usable carrier structure comprises a carrier frame and a removable stretchable carrier base supported thereby. A tacky adhesive layer is disposed on the carrier base, and semiconductor chips or other article(s) carried adhere to the adhesive layer. When it is desired to remove the article(s), an ejector displaces and stretches the carrier base. After the article(s) have been removed, the carrier base may be removed from the carrier frame which can be re-used to hold and transport article(s) after receiving a new carrier base.

This Application is a division of U.S. patent application Ser. No.09/915,122 filed Jul. 25, 2001, which claims the benefit of:

-   U.S. Provisional Application Ser. No. 60/220,915, filed Jul. 26,    2000;-   U.S. Provisional Application Ser. No. 60/223,810, filed Aug. 8,    2000;-   U.S. Provisional Application Ser. No. 60/227,463, filed Aug. 24,    2000;-   U.S. Provisional Application Ser. No. 60/228,196, filed Aug. 25,    2000; and-   U.S. Provisional Application Ser. No. 60/234,709, filed Sep. 22,    2000.

The present invention relates to a carrier structure for small items,and in particular to a re-usable carrier structure.

In semiconductor processing, simple adhesive dicing tapes are often usedfor holding wafers during operations such as lapping and dicing. Manyconventional dicing tapes employ lower temperature pressure sensitiveadhesive layers such as acrylic adhesive that will disintegrate attemperatures above 200° C. and yet employ a flexible PVC liner orsubstrate that will change shape at temperatures above 65-70° C. Mostflexible and stretchable polymer substrates are not able to withstandhigh temperature without degradation and/or change of shape ordimension. Flexible semi-crystalline polymers, such as PVC,polyethylene, and the like, will melt and thus change shape attemperatures below 150° C. In order to maintain shape above thistemperature, the polymer film substrates must be cross-linked, however,most cross-linked polymer films such as nitrile or butadiene rubber,cannot tolerate extended use at temperatures above 150° C. withoutsignificant degradation. While some silicone rubbers can be used forhigh temperature applications, in most cases, the adhesive layer mustalso be silicone-based. Silicone based adhesives typically leaveundesirable residues on the dice or components after they are removed.

Many carrier tape-and-reel packaging arrangements use pressure sensitivetape for transporting electronics and electrical parts. Some employ aspecific material composition and film adhesive for the specificapplication of release-on-command, i.e., controlled release of adhesionby exposure to ultraviolet (UV) light.

UV-releasing pressure-sensitive adhesive tape is used in the dicing ofsemiconductor wafers to form a structure specifically suitable forhandling dice during transportation in replacement of conventionalcarriers made with silicone gel, however, the structure is aone-time-use only carrier which is costly.

Some carriers use a permanently tacky layer deposited into formedpouches of standard tape-and-reel carriers for retaining devices, andthe material within the pouch may be punched out or gapped to reduce thetack strength for easier release. These pouches and punch-outs aredisadvantageous because they have to be specifically made for each sizecomponent for ease of use in pick-and-place operations.

Conventionally, waffle packs and tape-and-reel packaging that havepockets designed for close tolerance with the dimension of chips orcomponents to be carried are used for carrying applications duringtransportation, particularly where positioning of the parts is not ascritical as for the pick-and-place applications, but such carriers areless useful when dice that are not protected need to be transported. Inthe case of bare dice, bare dice may be transported using the originaldicing tape or, in some cases, waffle packs. In the case of wafflepacks, the potential for collisions between the parts carried and thewaffle partitions may damage more fragile dice, particularly where thepockets of the waffle pack are not a tight fit to the dice.

Certain waffle packs, trays, and tape-and-reels used for handling diceand components have a silicone-gel coating in a box or tray. These gelssuffer from the disadvantage that they transfer silicone monomers and/oroligomers from the gel to the chips or components that are beingcarried. While silicone gel coatings may be improved to reduce materialtransfer, the basic problem of silicone migration will exist for anysilicone adhesive used in electronic industry.

Conventional carriers have permanent tacky layers and use mechanicalmeans, e.g., ejector pin sets and/or vacuum or suction, to reduce theholding strength to ease release of the part for vacuum pick-and-placeoperation, to ease the difficulty of removal of the die or chip from thetacky carrier. Packaging trays and containers using non-silicone tackygels have the same problem of difficult removal of dice.

U.S. Pat. Nos. 5,118,567 and 5,356,949 disclose an e-beam curableadhesive on an e-beam transparent base sheet. In these patents, theadhesive tape is diced with the semiconductor wafer and not detachedfrom the resulting chips; rather, the cured tape is re-tackified byheating and becomes the adhesive by means of which the chips are nextattached to the larger component. Clearly, this adhesive will not bedesirable for every application, including those which requireattachment by soldering.

Accordingly, there is a need for a carrier structure that can be re-usedeasily and economically. It would be desirable that the carrierstructure can resist thermal deformation at the high temperatures atwhich many manufacturing processes are commonly conducted, at leastabout 80° C. One aspect of this need is for a carrier structure thatresists deformation at temperatures of about 100-150° C. at which wateris usually baked off electronic components. Another aspect is for acarrier structure that resists deformation at temperatures of about220-350° C. at which soldering operations are usually conducted.

A re-usable carrier structure according to the present arrangementcomprises a carrier frame defining at least one carrying space, and aremovable carrier base disposed in the at least one carrying space ofthe carrier frame. A tacky adhesive is disposed on the removable carrierbase, wherein an article may be held by the tacky adhesive and carriedon the removable carrier base of the carrier structure. The article isremovable leaving the removable carrier base and tacky adhesive thereonon the carrier frame, and the removable carrier base is removable fromthe carrier frame so that the carrier frame is available to be reusedwith another removable carrier base.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description of the preferred embodiments of the presentarrangement will be more easily and better understood when read inconjunction with the FIGURES of the Drawing which include:

FIG. 1 is a cross-section schematic diagram of a two-layer carrierstructure according to the arrangement, comprising a carrier liner andan adhesive layer.

FIG. 2 is a cross-section schematic diagram of a three-layer carrierstructure according to the arrangement, comprising a carrier liner, across linkable adhesive layer, and a non-cross linkable adhesive layer.

FIG. 3 is a cross-section schematic diagram of a four-layer carrierstructure according to the arrangement, comprising a carrier liner, across linkable adhesive layer, and adhesive liner, and a non-crosslinkable adhesive layer.

FIG. 4 is a cross-section schematic diagram of an embodiment of thecarrier structure according to the arrangement, wherein the carrier isin the form of a tape, and the carrier tape liner forms a trough.

FIGS. 5A and 5B are a cross-section schematic diagram and a plan viewschematic diagram, respectively, of an embodiment of the carrierstructure according to the arrangement, wherein the carrier is in theform of a tape.

FIG. 6 is a cross-section isometric schematic diagram of an exemplaryembodiment of the carrier structure according to the arrangement,wherein a ledge in the carrier base serves as a support for a removableradiation-transparent insert, upon which the adhesive layer is disposed.

In the Drawings, where an element or feature is shown in more than onedrawing figure, the same alphanumeric designation may be used todesignate such element or feature in each figure, and where a closelyrelated or modified element is shown in a figure, the samealphanumerical designation primed may be used to designate the modifiedelement or feature. Similarly, similar elements or features may bedesignated by like alphanumeric designations in different figures of theDrawing and with similar nomenclature in the specification. It is notedthat, according to common practice, the various features of the drawingare not to scale, and the dimensions of the various features of thedrawing are not to scale, and the dimensions of the various features arearbitrarily expanded or reduced for clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The carrier of the present arrangement is useful in many fields, such asin manufacturing, where many small items or devices must be transportedor held in such a manner that they are secure from physical orenvironmental damage, or are held steady during a manufacturingoperation, yet the items must be released from their holders in order tobe processed further or assembled into other items.

The carrier structure of the present arrangement can be used, forexample, as a holder for silicon or other semiconductor wafers duringlapping and dicing and other semiconductor processing operations afterwhich the wafer must be easily releasable. The present arrangement alsofinds application in such apparatus as a low tack adhesive film or layerwith a waffle-pack, a tape-and-reel cavity, or a simple carrier tray forbare dice, surface mount components, and other electrical and/orelectronic parts and/or devices, as well as mechanical and other partsand devices.

The definitions below apply to certain terms as they are used herein,unless otherwise limited in specific instances, either individually oras part of a larger group, or by the context.

As used herein, the term “about” means that dimensions, sizes,tolerances, formulations, parameters, shapes and other quantities andcharacteristics are not and need not be exact, but may be approximateand/or larger or smaller, as desired, reflecting tolerances, conversionfactors, rounding off, measurement error and the like, and other factorsknown to those of skill in the art. In general, a dimension, size,formulation, parameter, shape or other quantity or characteristic is“about” or “approximate” whether or not expressly stated to be such.

“Thermal-UV” means either ultraviolet radiation, heat, or bothultraviolet radiation and heat. Heat may include conventional thermalheating, infrared, ultrasonic, microwave or other energy.

“Cross-linking” and “curing” are used interchangeably herein to signifyreactions wherein polymer molecules become covalently bound to oneanother.

The terms “objects”, “chips”, “wafers”, “dice”, “devices”, “components”,“items” and “parts” are used interchangeably to refer to semiconductordice, packaged components, modules, passive components, mechanicalparts, pellets, pills, any electronic or electrical parts or devices,and/or any other items or devices or objects which may be transported orheld as part of any storage, handling, transport, shipping,manufacturing, application, or other process.

The terms “manufacturing process”, “process”, and “operation” are usedinterchangeably herein to refer to any method involving moving ortransporting or handling an object, attaching it to or releasing it fromanother object, or changing a component or object physically orchemically or electrically. Processes and operations also include thetransportation and/or shipping of components to or from the location atwhich they are to be made, processed, handled, stored and/or used.

The terms “base”, “substrate” and “liner” are used interchangeablyherein to refer to layers whose function is to support and/or to providemechanical strength to one or more other layers.

“Energy” and “radiation” and “electromagnetic radiation” are usedinterchangeably herein. “EMR” means electromagnetic radiation of anywavelength, and includes, for example, visible light, ultraviolet (UV)light, infrared radiation, radio waves, microwaves, e-beam radiation,and the like.

“Tacky” and/or “tackiness” generally refers to a property of an adhesiveto adhere to or stick to what it comes into contact with, and is oftenused in relation to so-called pressure-sensitive adhesives.

“Peel strength” is a measure of the strength of the bond provided by anadhesive. Peel strength is typically measured by bonding a one-inch widetape of a material to a planar surface using the adhesive, and thenpeeling the tape from the surface at a constant rate and measuring theforce needed to peel the tape. The tape is peeled at an angle of about180° with respect to the surface, i.e. the tape is peeled back overitself close to the surface in a direction parallel to the surface. Peelstrength is typically expressed in units of the peeling force divided bytape width, commonly in “grams per inch” (“grams/inch or “gm/in”) in theUnited States. While the commonly used grams/inch (“gm/in”) is in mixedSI and English units, it may be converted to purely English units orpurely SI units by standard conversion factors.

Carrier structures of the present arrangement comprise a cross-linkabletacky adhesive layer 20 that loses a substantial portion of its adhesivestrength upon exposure to thermal-UV or other suitable forms of energy(EMR) that activate cross-linking. The adhesive is preferablysufficiently tacky to hold objects securely enough for the manufacturingor other process, e.g., during semiconductor lapping and dicingoperations. When the operations requiring secure holding are completed,the tacky layer is exposed to cross-linking radiation. As the tackylayer is cross-linked, it loses its tackiness, and the parts are easilyremoved from the carrier structure. This reduction of tackiness andadhesion may be induced almost instantaneously by curing of the tackylayer with EMR, preferably with thermal-UV energy.

Preferably, the tacky layer crosslinks to lose the majority (e.g., about51% or more) of its adhesive strength upon exposure to cross linkingenergy, and more preferably loses about 70% or more of its adhesivestrength.

FIG. 1 is a cross-section schematic diagram of a two-layer carrierstructure comprising a carrier liner 10 and a cross-linkable adhesivelayer 20. Carrier structures of the present arrangement may also includecross-linkable adhesive layers 20 comprising a combination of permanenttacky controlled peel strength adhesive and thermal-UV releasingadhesive within a single layer 20. Thus, differential peel strength isproduced after thermal-UV exposure. The adhesive layer 20 first releasesthe chips or other objects carried and then releases the carrier base10, enabling the replacement of adhesive layer 20 for reuse of typicalcarrier base 10. Such a combination adhesive preferably releases bothchips 60 and liner 10 without leaving a residue, and also preferably hasgreater adhesion to liner 10 than to the chip or other object 60 carriedso that the chip is released more easily than is the liner 10, i.e. ithas a different release profile from the chip 60 than from liner 10.

With the use of thermal-UV releasing tacky layer 20, the adhesion isvery strong during the transporting and handling, as long as thecross-linkable layer 20 is protected from exposure to thermal-UV energy.The release of the chips 60 is made dramatically easier by exposure ofthe tacky layer 20 to thermal-UV, generally right before thepick-and-place operation or other use or process.

The adhesive layer 20 or tacky layer 20 is preferably a cross-linkedpolymer so that residues on the dice or item after release from thecross-linkable adhesive layer 20 are minimized. The adhesive layer 20 ispreferably not made with silicone monomers and/or silicone oligomers soas to minimize the problem of silicone migration. Silicone monomer andoligomer residues are known to hinder or even prevent adhesion oflater-added materials, such as epoxy adhesive and solder.

The adhesive layer or tacky later 20 is also preferably adjustable todifferent peel strengths while maintaining its low residue transfercharacteristics. The peel strength of available suitable adhesives istypically in the range of about 200 gm/in to over 1000 gm/in. Peelstrength may be adjusted by adjusting the ratio of uncured liquidmonomer and/or oligomer to the solid binder used. Increasing the liquidportion of a high-molecular weight monomer or oligomer will typicallyproduce greater tackiness and higher peel strength.

It is contemplated that heat or any other type of EMR, such asmicrowaves, UV, IR, and the like, will be effective to cure the tackylayer 20, although some forms of energy may require more time to cureand activate certain cross-linking functionalities. Any type of energycan be used, however, if properly chosen for compatibility with suitablebase materials. UV-thermal cross linking is presently preferred for manyapplications due to the ease with which release of the carried objectsmay be controlled, particularly where the processing of the carriedobjects is performed at elevated temperature. An example thereof is thethermal baking of devices at over 100° C. to drive off moisture that mayhave been absorbed by such objects. Thermal curing, where utilized, ofthe thermal-UV releasing structures is typically performed at 50-200° C.depending on the specific application.

In some embodiments, the cross-linkable adhesive layer 20 comprises oneor more non-silicone gel-like pressure sensitive adhesives. Suitableadhesives include, for example, types CGL7050-X and UVA7050-X adhesivesavailable from AI Technology Inc. located in Princeton, N.J. Each ofthese adhesives has a degree of tackiness varying from about 20 to 2000gm/inch with a primarily non-polar backbone molecular structure, andeach is proven to have reasonably good tack on a silicone liner 10. Inother embodiments, the same tacky layer components can also be used onother suitable liners 10 including those with both higher and lowersurface energy.

In some embodiments, a thermosetting elastomer with epoxy functionalitysuch as cured adhesive films with properties similar to types ESP7450 orCC7450 adhesive (also available from AI Technology in Princeton, N.J.)is utilized in the cross-linkable adhesive layer 20. Types ESP7450 andCC7450 adhesives are both flexible adhesives capable of toleratingoperation at temperatures of about 350° C., at least intermittently,without major weight loss or loss of mechanical properties, such as theability to be stretched by a factor of over 30% without failure. Whilesilicone rubbers may be made to provide such high-temperature and/oradhesion and release properties, silicones do not release cleanly, butleave undesirable silicone residue.

In certain embodiments useful in semiconductor wafer processing, thetackiness during wafer lapping and dicing should be high, e.g., over 200gm/inch. When the tackiness is over 200 gm/inch, however, the dicedparts may be difficult to remove. Thus, in some cases, UV curable ore-beam curing polymer can be cured to cause additional cross-linking toreduce the tackiness to a suitable level (e.g., less than about 50gm/inch of peel strength is desirable). In such cases, the tacky layer20 made with a UV curing adhesive such as types UVA7150-X or UVR500 orUVR1000 UV-releasing adhesives with tackiness before curing suitablyadjusted will be more suitable. Types UVA7150-X or UVR500 or UVR1000UV-releasing adhesives are available from AI Technology, Inc. inPrinceton, N.J., and can be used as a coating on the cured ESP7450 orCC7450 adhesive layer 20. These adhesives are high enough in tackinessand molecular weight that once the coating is exposed to UV, thetackiness may be reduced from the range of about 200-5000 gm/inch toabout 20 gm/inch to facilitate pick-and-place removal, but still firmlyretain the diced parts during transportation.

It is noted that the tackiness adjustment desirably is made with thesize, weight, and nature of the object 60 to be carried in mind. Wherethe object 60 has a relatively large smooth area that contacts the tackyadhesive, as is the case for a large area semiconductor chip, a lessertackiness is sufficient. For an object 60 that has a contact area thatis only a relatively small portion of its size, as is the case for afinned surface of a heat sink device, somewhat greater adhesion may bedesired.

A product that has similar characteristics of tackiness, but that doesleave some residue may be satisfactory if, should residue betransferred, the residue does not interfere with bonding to commondie-attach adhesives, electrically conductive adhesives and solder.Those of skill in the art are aware of the difficulty of engineering apolymer with complicated application properties desired: a polymerstructure that is both flexible and gel-like with controlled tackinessthat will not change even after extensive aging and exposure to hightemperature or ambient conditions.

Presently, it is preferable that such polymer should be based on epoxyfunctionality so that it is more compatible if any residue were to betransferred onto the parts. In some embodiments, commercial gel-likecoating or adhesives, such as types CGL 7010 and CGL 7050, and UVG 7550(also available from AI Technology Inc. in Princeton, N.J.) have beenfound to be useful for such applications.

Adhesives of the types utilized in other commercially availableUV-releasing dicing tapes could be utilized in the present arrangement.Examples include the adhesives of types 1042R and 1044R tapes availablefrom Ultron Systems Incorporated located in MoorPark Calif., and of theAdwill-D series, such as types D-218, D-410T and D-670, available fromLintec Corporation of Japan or from Lintec Research Boston, Incorporatedof Tempe, Ariz.

All of these polymeric adhesives have a single epoxy functionality and ahigh molecular weight. Some of the commercially available gels have anamine functionality that has been induced to cross-link with less thanone functional equivalent of epoxy. These amine-functional polymersremain gel-like and do not completely form a firm film withelastomer-like properties. This manipulation of the functionality iscommonly used in the pre-polymerization of amine curing agent. But theextent of cross-linking must be much higher as the molecular weight ofthe polymer must be very high, effectively a molecular solid, to preventresidue transfer. Naturally, the same effect would be produced withsimilar levels of cross-linking functionality and an excess of epoxyover amine groups.

In some embodiments, the tacky adhesive layer 20 used as UV releasingwafer-mounting film comprises types UVR500, UVR1000, WMR500 and/orWMR2000 adhesives available from AI Technology, Inc., types 1042R and1044R from Ultron Systems Inc., and types D-105V and D-210 availablefrom Lintec Corporation.

The application of cross-linkable adhesive gels onto suitable substratesin the form of trays, waffle-packs (with or without pockets), andtape-and-reels (with or without specific pockets), is substantiallydifferent from the application of conventional silicone gels. Both thechemistry of forming of gel-structure and the availability of differenttackiness for the specific applications of carrying duringtransportation give substantial improvements over typical silicone gels,which have no engineering capability of tackiness nor any ability to bemodified to adhere to bonding adhesives or solder with or withoutpre-cleaning. In the case of some silicone gels, even cleaning withsuitable solvent is not easy and tends to cause contamination even ofother work areas. Such a silicone contamination problem is highlyundesirable and must be avoided in most electronic applications, such assemiconductor and board assembly applications, as well as in mechanicalapplications.

More recently, there is increased use of flip-chip devices whereby therelative repeat position (i.e., pitch, or center-to-center spacing) ofthe dice must be quite accurate to facilitate alignment duringpick-and-place applications. This is also the case for certainball-grid-array (BGA) packages having finer dimensions, such as fineconnection pitch. In such cases, gel-like carrying layer 20 can providemore accurate positioning, and avoids the problem of silicone transferfrom a silicone gel. The problem of silicone residue tends to becomecritical as the size and pitch dimensions of the device connections,such as solder bumps, become smaller. Any defect in soldering within themany bond pads of a BGA package could cause a complete device failure.Thus, silicone migration is becoming even more of a problem, andsilicone is to be avoided where possible. For epoxy-based cross-linkablegel adhesives, cleaning, if needed, will not cause residuemigration-induced soldering or adhesion problems because thenon-silicone polymers have a relatively high surface energy.

Carrier structures of the present arrangement, for example, as alsoshown in FIG. 1, also comprise a carrier liner or base 10. At least aportion of liner 10 is transparent to EMR, and preferably transparent toUV and/or e-beam radiation. Liner 10 may also be thermally conductive toincrease the efficiency of the cross linking of the tacky layer 20 wherelayer 20 is thermally cross-linkable.

In certain embodiments, the carrier structure may have anti-staticproperties. This anti-static effect may be achieved with conductive meshoverlaid on or embedded in the carrier liner 10. If conductive meshoverlay is to be used, it can be printed using conductive inkcontaining, for example, carbon black or carbon fibers. Alternatively, afine metal mesh can be laminated over the surface of the substrate 10using a layer about 5-15 mils thick of polyester or other high glasstransition temperature (Tg) thermoplastic, or a blend of high Tgthermoplastic and thermosetting polymers. An appropriate conductive meshover the transparent carrier substrate or liner 10 will notsignificantly hinder the transmission of radiation to cure andde-tackify the cross-linking adhesive layer 20.

FIG. 2 is a cross-section schematic diagram of a three-layer carrierstructure comprising a carrier liner or base 10, a cross linkableadhesive layer 20, and a non-cross linkable adhesive layer 30. In orderto extend the concept of the use of “release-on-command” structure, i.e.by application of suitable EMR, a laminate of adhesive films may beused. This laminate film may have two layers, each with differentadhesive characteristics. The layer 20 that contacts objects 60 to becarried such as dice or chip parts 60 may be pressure sensitive withsubstantial bonding strength of about 100-5000 gm/inch peel strengththat will be reduced to less than about 50 gm/inch after cross-linkingupon exposure to UV light, heat or other suitable electromagneticenergy, such as microwaves. The electromagnetic energy should besufficient to overcome the activation energy barrier of the molecularreaction or reactions, e.g., cross linking that will reduce the adhesioncharacteristics.

The second layer 30 of the adhesive laminate should be coated with astrong adhesive, e.g. about 100-5000 gm/inch, that will not bedramatically affected by thermal-UV or other radiation exposure. Thissecond, non-curable adhesive layer 30 should be easily removable fromthe carrier base 10, so that the carrier base 10 can be reused afterapplication of a new adhesive laminate. Thus, second layer 30 has adifferent release profile than does first layer 20.

In typical embodiments, the thickness of the non-curable adhesive layer30 is about 0.5 to 5.0 mils; however, this may vary widely depending onthe demands of the application. The non-curable adhesive should notleave residues on the UV-transparent portion of the carrier. Preferably,adhesion of the non-curable adhesive will not be affected by thermal-UVexposure, but if it is, adhesion should not drop by more than about 50%(and preferably much less than 50%) and should definitely retain atleast about 100 gm/inch peel strength.

What is important is that the bond strength between layer 20 and theobject carried decrease by a substantial amount to a lower strength thanthat between layers 20 and 30 and that between layers 30 and 10Preferably the non-curable layer 30 comprises a controlled releasepressure sensitive adhesive that is essentially inert to thermal-UVexposure. Preferably this non-curable tacky layer 30 will retain itsstrength of adhesion when exposed to UV or other forms of curing energyused to reduce the peel strength of the cross-linkable layer 20 of tackyadhesive.

Preferably, the non-curable layer 30 is not silicone based, or notsubstantially silicone-based. The cost of the adhesive laminate filmsshould be low so that disposal of the laminate after use in itsapplications will be economically feasible. Preferably, the non-curablelayer 30 has a substantial body as realized with a blend ofthermoplastic polymers and less than about 80% of the reacting ornon-reacting liquidous portion.

Preferably, the non-curable layer 30 has a gel-like structure, but notsubstantial segments of molecular structure with low Tg, i.e., Tg belowambient temperatures. Residue transfer to the carrier base 10 may bereduced by maintaining sufficient cross-linked density. Preferably, thenon-curable layer 30 is modified with sufficient polarity in itsmolecular structure to facilitate ease of removal with common solventssuch as isopropanol (IPA), acetone, 2-butanone (MEK), and the like.Preferably, the non-curable layer 30 is made with functional groups thathave a substantial proportion of mono-functional groups. Mono-functionalgroups promote curing with sufficient tackiness and peel strength, i.e.,greater than about 200-5000 gm/inch.

Preferably, the non-curable layer 30 is synthesized from a blend ofthermal plastic elastomer or high molecular weight elastomer andcross-linkable functional monomers. Preferably, such monomers arecompletely cross-linked in the course of the synthesis with thermal orUV or e-beam or microwave or another appropriate form of energy.

FIG. 3 is a cross-section schematic diagram of a four-layer carrierstructure comprising a carrier liner 10, a cross linkable adhesive layer20, and adhesive liner 40, and a non-cross linkable adhesive orpre-cross-linked adhesive layer 30. In some embodiments, the adhesivelayers may be disposed on the surface of an adhesive base or liner 40.This liner 40 should be transparent to UV radiation, or in generalshould transmit whatever type of radiation is used to cross-link thetacky layer 20. Preferably, the adhesive liner 40 comprises low costmaterials such as polyester, acrylic, polycarbonate or other highersurface energy plastic sheet. The adhesive liner 40 should betransparent to UV or microwave or whatever type of EMR is used tocrosslink the tacky layer 20. More preferably, the adhesive liner 40 isresistant to deformation at the elevated temperatures at which thecarrier structure is intended to be used. One advantage of the adhesiveliner 40 is that it facilitates the re-use of the carrier structure bymaking the removal of the adhesive layers 20 and 30 from carrier base 10easier.

The above embodiments provide for electromagnetic radiation to penetratethrough the carrier structure in order to cross-link the tacky layer 20,as dice and components 60 are typically not transparent to cross-linkingradiation. To the extent that the tacky layer 20 is cross-linked bythermal energy, transparency to EMR is less of a concern, althoughincreasing the thermal conductivity of the carrier structure increasesthe efficiency of the cross-linking. Thus materials such as transparentpolystyrene, acrylics, polycarbonate or other EMR-transparent materialsare preferably used for molding the carrier structure base 10.Alternatively, the carrier liner 10 may be physically modified, as bythe provision of a suitable portion or cavity or window formed in theliner to transmit the EMR. Preferably, the transmission properties ofthe portion and/or physical modifications are sufficient to allow thetack strength to be reduced to less than about 30% of the original(pre-EMR exposure) value so that the carried devices are readilyreleased during pick-and-place operations.

FIG. 4 is a cross-section schematic diagram of an embodiment of thearrangement wherein the carrier is in the form of a tape, and thecarrier tape liner 10 a forms a trough. To maximize opportunities forre-use, it is desirable that the carrier structure be compatible withcomponents or other items 60 to be carried of varying sizes, and not bespecifically sized for a particular object. The specific sizes of thecarrier structures may or may not follow industrial standards such asthose established by JEDEC (Joint Electronics Device EngineeringCouncil) or others.

To this end, the use of a trough configuration tape 10 a rather thanformation of multiple specific size pockets or pouches facilitatesflexibility. In embodiments which the carrier structure is a tape, forexample, the width of the carrier tape determines the only restrictionon the size of the component 60, and tapes of the same width withdifferent pocket lengths need not be manufactured. Thus fewer versionsof these tapes, and the reels on which they are would in tape-and-reelpackaging are required. The economics of scale thus obtained furtherreduce the manufacturing cost and therefore the cost of using suchtapes. In addition, the application of the adhesive layer 20 to a longtrough-type carrier tape liner 10 a is simpler and more economical thanthe application of an adhesive layer only in the many pockets of apocket-type liner.

The carrier base or substrate 10 a is preferably of suitable rigidityand thickness to control or conform to the flatness of the partscarried. Typically, the cavity or trough of the carrier base 10 a is atleast as deep as the height of the component or device that it isintended to hold. The carrier base 10 a may also be providedadvantageously with such other features as are well known in the art,for example, sprocket holes or other means of guiding and/or feeding acarrier structure in the form of a tape. Some of these advantageousoptional features are shown in the embodiment depicted in FIGS. 4 and 5described herein.

In the present arrangement, high temperature polymers are used as thecross-linkable adhesive of tacky layer 20 and also as the liner 10, 10 afor the adhesive 20. These polymer and adhesive layers may be engineeredso that the onset of significant degradation occurs at temperaturesabove about 300° C., and preferably above about 350° C., as measured bystandard thermogravimetric analysis (e.g., measurement of weight loss attemperature increase rate of 10° C. per minute under standardatmospheric conditions).

In addition to the thermal stability of the polymer molecular structureunder an air atmosphere, this carrier base 10, 10 a is preferably apolymer with sufficient cross-linked density such that the tackyadhesive film 20 will not easily or permanently deform under themechanical forces to which it will be subjected under typicalmanufacturing conditions. On balance, however, the carrier base 10, 10 ashould be slightly flexible, for example, to permit realistic or evengenerous tolerances in alignment with manufacturing equipment.Accordingly, it is preferred that a sufficient portion of the polymerstructure have a glass transition temperature (Tg) substantially belowambient temperature and preferably below about 20° C.

Carrier structures of the present arrangement are laminate films with amechanical support liner 10, 10 a that is typically about 1-10 mils orabout 25-250 microns in thickness. Thicker liners 10, 10 a can be usedfor special cases, but for economic reasons, thicknesses of about 3-6mils are preferred.

Most of the conventional liners currently used are plasticized PVC filmthat is both inexpensive and has reasonable bonding characteristics,with higher surface energy (over about 40 dyne/cm) to facilitateadhesion to the acrylic pressure sensitive adhesives that commonlyconstitute the cross-linkable tacky layer being used. While PVC linersare low in cost, they are deformed easily at temperatures above 65-70°C. and thus cannot be used for high-temperature or heat-generatingoperations, such as lapping or machining. For example, lappingoperations to reduce the thickness of a silicon wafer from 20 mils to1-2 mils generate a substantial amount of frictional heat, with in situtemperatures easily exceeding 70° C.

Other engineering plastics such as polyester and polyimide, while usefulfor higher temperature applications and having relatively high surfaceenergy of adhesion, lack flexibility and stretchability due to theirrelatively high modulus of elasticity, typically 1,000,000 psi orgreater. Stretching by a factor of about 10-100%, which obtains fromflexible adhesives having a much lower modulus of elasticity, may bedesirable to mechanically help separate the parts carried from thecarrier structure, e.g., after dicing as in the case of a silicon waferdicing operation. Thus, engineering plastics are not optimal as carrierstructure bases.

Among the conventional elastomers that can be stretched, cross-linkedelastomers such as silicone rubbers of both the conventional methyl-typeand vinyl-type are quite useful in terms of their ability to toleratehigher temperature; however, most acrylic-based pressure sensitivepolymers will not adhere well to these substrates and they leaveundesirable silicone residue.

A polymer with low enough surface energy to form good bond to thesilicone layer must be used. There are very few such pressure sensitivemedia that can bond to silicone liner 10, 10 a, which tends to have thelowest surface energy surface among all polymer structures. In any case,silicone pressure sensitive layers share the common problem of freesilicone monomer residue transfer which is to be avoided Examples ofsuitable substrates or liners 10, 10 a for such non-silicone gelcross-linkable adhesives are conventional ABS, PET, polycarbonate,polyester, high impact polystyrene, or polysulfone, polyethersulfone, orother engineering plastics or liquid crystal polymers. This substrate10, 10 a can be metal or ceramic if suitable plastics cannot providespecific desirable properties, with at least portions being of asuitable EMR transparent material. In most high volume applications,polymers that can be molded offer much lower cost and great versatilityin terms of shape and format. Carrier liner 10, 10 a preferablycomprises a non-silicone dielectric such as AI Technology type ESP7450flexible adhesive which includes cross-linked epoxy with highflexibility, or a combination thereof with a silicone material.

In the case of embodiments intended for use at the lower end of theelevated temperature range, e.g. about 80-150° C., or even at highertemperatures up to about 250° C., some conventional non-silicone rubbersuch as nitrile or butadiene, or other elastomers may be used. As longas the liner is mechanically and molecularly stable when exposed to thehighest temperature of the operation, it may be used for suchapplications. The elastomeric liners preferably do not includefiberglass or mesh or other support or filler that may impede itsability to be stretched.

FIGS. 5A and 5B are a cross-section schematic diagram and a plan viewschematic diagram, respectively, of an embodiment of a carrier structurewherein the carrier is in the form of a tape 10 b having a cover 50. Thecarrier structures of the present arrangement may optionally be providedwith an anti-static cover 50 with either a flat tape as illustrated orwith a trough tape structure 10 b. Such a cover structure 50 may havethermal-UV blocking properties and is typically about 5-15 mils thickand may be comprised of PET or another relatively rigid film to providemechanical protection.

Cover 50 may be secured to tape 10 b by tacky adhesive layer 20, asillustrated, and so is conveniently released by the same exposure to EMRthat is utilized for releasing the chips or other objects carriedthereon.

Tape 10 b is a long strip of carrier base 10 b material that is slightlywider than is the strip of tacky thermal-UV adhesive 20 disposedthereon. Carrier tape 10 b may have drive sprockets illustrated by thecircular holes along either one or both edges thereof, which holes serveas a means to impart motion (drive) the tape and/or for aligning thetape with respect to apparatus such as pick-and-place equipment.

Alternatively and optionally, a cavity or window may be formed in acarrier structure 70 to allow energy (EMR) to pass through carrier base10 to expose and cure the tacky layer 20 to achieve similar reduction oftackiness of the areas exposed.

FIG. 6 is an isometric schematic diagram of an exemplary embodiment of acarrier wherein a ledge 11 in the carrier structure 70 serves as asupport for a radiation-transparent carrier base insert 10, upon whichthe adhesive layer 20 is disposed. Adhesive layer 20 may be any one ofthe two-layer, three-layer and four-layer embodiments described above.An object 60, such as a semiconductor chip or other electronic componentis also shown in place on adhesive layer 20. Alternatively, atransparent rigid backing substrate 10 may be used. The desirablecharacteristics of such a backing substrate 10 include transparency tothe EMR that is used to cure the tacky layer, preferably transparency toUV, microwave or e-beam radiation. Suitable rigid backing substrates 10include, for example, inorganic glasses such as quartz, silicate glassesor organic glasses such as polycarbonate, polystyrene, and acrylic.Desirably the rigid backing substrate 10 is low enough in cost so thatit is economically feasible to discard it after each use.

Also alternatively, and/or optionally, the laminate of adhesive layer 20is protected from cross linking by UV light before the carrier structureis used by means of a UV barrier release liner 50. Typically, suchrelease liner/cover 50 is placed over tacky layer 20 and over carrierbase 10 to block EMR that would crosslink adhesive layer(s) 20 and willbe removed from the UV curable tacky layer 20 prior to use. Such blockmay be restored or applied after the object 60 is placed on tacky layer20 to block cross-linking EMR until such time as it is desired torelease object 60. The carrier base platform 10 may be removable ornon-removable from the waffle pack, tape-and-reel, and JEDEC trayconfiguration, as is desired.

Where carrier structure 70 is a JEDEC carrier, the useful and UV activeareas of base 10 have dimensions typically about 5″ by about 12″. Thetray has a ledge 11 for releasably supporting carrier base 10 andretaining lips 12 at least on two long side of the tray so that theplatform and the tray can be slightly bent to allow insertion of theremovable platform 10. The platform 10 is typically about 1/16″ thick.It is apparent that platforms 10 of different thickness or shape or sizecan be used to create non-standard carriers. The removable platform 10is preferably constructed with a UV transparent substrate such as glass,acrylic, polycarbonate, and the like. If high temperature exposure isrequired, for example, baking at 150° C. for an extended period of timeto remove moisture from the components, non-shattering glass orcross-linked plastics are often preferred.

In some embodiments, a single layer 20 of thermal-UV curable liquidousmixture with a high temperature stable polymer is made with a typicalratio of liquidous portion in the range of about 30-80% and preferablyin the range of about 40-60%. This ratio will assure the adhesive layer20 has adequate film forming characteristics without an adhesive base orliner 40. Typically a thicker adhesive film 20 in the range of about2-10 mils thickness will be used if the liner is omitted. The adhesivefilm 20 will be sandwiched between two UW-opaque release liners toprevent UV cross-linking when not desired. The adhesive-liner assembly10, 20 can be die-cut to specific preform dimensions to fit the activeand useful areas of the platform 10 and carrier structure 70.

In embodiments without a liner 40 for the adhesive layer 20, theadhesive film 20 is preferably synthesized from polymers and liquidousreacting portions having higher surface energy or polar structures. Themost preferred molecular backbones for both the polymers and thereacting liquids should have surface tension or energy of more than 50dyne/cm and preferably above 75 dyne/cm. The higher the surface tensionin comparison to the substrate that it is applied onto, the easier itwill be to release upon thermal-UV-curing. The compatibility and filmforming characteristics are most complete in the range of polymer blendof 20-80% of solid polymer, the rest being that of the reactingliquidous portion. Some of the higher energy polymers include acrylics,polyvinylidene chloride, polyvinylidene fluoride, polyvinyl chloride,polyvinyl fluoride, and the like. Most of these polymers can be used toblend with the polar acrylate and epoxy liquidous monomers or oligomers.Typical thermal-UV, cationic catalysis, or other means of curing may beused to facilitate such thermal-UV releasing film 20.

All of these high-surface-energy polymers may be used for baking outmoisture, e.g., at about 150° C. If extended exposure to highertemperature of about 200-350° C. for a few minutes must be used, themore useful polymers will be those of polyvinylidene fluoride or itscopolymer. Some of block co-polymers such as Kraton G series made byShell Chemical Company or similar thermoplastic elastomer resin withhigh temperature stable backbone may be used. Preferably the adhesivehas a higher and more permanent adhesion to the carrier base film orliner 10 than to the items to be carried, i.e. has a different releaseprofile to carrier base film or liner 10, 10 a, 10 b than to the items,and that the adhesive layer 20 be of sufficient thickness (typicallyabout 1-5 mil) to hold parts with slightly different flatnesstolerances.

In some embodiments, the release of the parts is aided by an ejector pinassembly as is conventional. The pins are projected towards the partsthrough a flexible layer 10, 10 a, 10 b, thus raising the parts foreasier grasping. In addition, the flexible layer 10, 10 a, 10 b ispreferably deformed by the ejector pins so that it detaches partiallyfrom each part. In this way, the force necessary to remove the partsfrom the adhesive layer 20 is decreased because of the loss of adhesioncaused by thermal-UV curing of adhesive layer 20 as well as by thereduced contact area between the adhesive and the part.

While the present invention has been described in terms of the foregoingexemplary embodiments, variations within the scope and spirit of thepresent invention as defined by the claims following will be apparent tothose skilled in the art. For example, it will be apparent to those ofskill in the art that the carriers of the present arrangement might betrays. Such trays may hold one or more components or items and mayoptionally be divided into small sub-compartments. Carriers such aswaffle packs and JEDEC trays are examples of tray embodiments.

Typical embodiments include waffle packs and JEDEC trays using athermal-UV releasing tacky layer over a UV transparent substrate. Thetacky layer is designed to lose the majority, and preferably more thanabout 70%, of its adhesive strength upon exposure to UV or othersuitable form of energy to activate curing. These carriers may bere-used by removing the thermal-UV layers and applying a fresh tackylayer.

In other embodiments, the carrier structure is in the form of a tape.Tapes are a very compact and convenient means for transporting andholding many parts in a relatively small volume. Tapes also simplifypick-and-place operations by enabling facile placement of each part inone set location for removal from the carrier tape, in contrast with thetwo dimensional array that is typical of trays.

In a waffle pack, for example, a repeat pattern of holes in the base 10,10 a, 10 b are spaced about 1/16″ to ⅛″ apart and spread evenly over thearea of the base of the tray, and the ejector pin-set has a reciprocalmatching arrangement similar to a male-female arrangement, such that thepins will pass through the holes to provide an ejection mechanism. Inthese embodiments, the flexible layer 10, 10 a, 10 b is preferably afirm, non-silicone elastomer with structural integrity, such as AITechnology types CC7450 or ESP7450. The flexible layer 10, 10 a, 10 bmay optionally support a tacky layer 20 in contact with the parts, andis attached to the carrier, preferably at least at its edges.

In embodiments comprising a removable platform 10 and a replaceablethermal-UV-releasing layer 20, it is estimated that each carrierstructure of the present arrangement can be used at least ten times ormore. This re-use provides significant savings in manufacturing costs.For example, if a typical JEDEC tray of $3.00 to $5.00 value is used tentimes or more, the cost is less than $0.30-$0.50 per use. It followsthat the cost of each tray usage per chip is also reduced by a similarfactor.

The cost savings extend to capital investments and costs of repair. Thefact that a standard carrier such as a JEDEC tray or universal tray canbe used avoids a typical tooling cost of $20,000 to $40,000 for a customcarrier. Even though the tape-and-reel are not typically reused, thefact that a universal tape arrangement can be used also saves the costof custom tooling and dramatically lowers the overall cost of ownership.

1. A re-usable carrier structure for carrying an article, comprising: acarrier frame defining at least one carrying space; a removablestretchable carrier base disposed in the at least one carrying space ofsaid carrier frame, said removable stretchable carrier base beingstretchable by about 10-100% or by over 30%, and being stable to resistdeformation by heat at temperatures less than or equal to about 80° C.;a tacky adhesive disposed on said removable stretchable carrier base;wherein an article may be held by the tacky adhesive and carried on thea tacky adhesive on the removable stretchable carrier base of saidcarrier structure, wherein the removable stretchable carrier base isstretched when displaced by an ejector for releasing an article carriedon the tacky adhesive on the removable stretchable carrier base; andwherein the article is removable leaving said removable stretchablecarrier base and tacky adhesive thereon on said carrier frame, andwherein said removable stretchable carrier base is removable from saidcarrier frame so that said carrier frame is available to be reused withanother removable stretchable carrier base.
 2. The re-usable carrierstructure of claim 1 wherein the carrier frame includes a waffle pack, atray, a JEDEC tray, a tape-and-reel, or a tape.
 3. The re-usable carrierstructure of claim 1 wherein said removable stretchable carrier base isstable to resist deformation by heat at temperatures less than or equalto about 300° C., or has anti-static properties, or is stable to resistdeformation by heat at temperatures less than or equal to about 300° C.and has anti-static properties.
 4. The re-usable carrier structure ofclaim I wherein said removable stretchable carrier base is stable toresist deformation by heat at temperatures less than or equal to about150° C., or has anti-static properties, or is stable to resistdeformation by heat at temperatures less than or equal to about 150° C.and has anti-static properties.
 5. The re-usable carrier structure ofclaim 1: wherein said removable stretchable carrier base definessub-compartments and the tacky adhesive is disposed in thesub-compartments; or wherein said tacky adhesive has a peel strength ofless than about 50 grams/inch; or wherein said tacky adhesive has a peelstrength of about 20-2000 grams/inch; or wherein said removablestretchable carrier base defines sub-compartments and the tacky adhesiveis disposed in the sub-compartments, and wherein said tacky adhesive hasa peel strength of less than about 50 grams/inch; or wherein saidremovable stretchable carrier base defines sub-compartments and thetacky adhesive is disposed in the sub-compartments, and wherein saidtacky adhesive has a peel strength of about 20-2000 grams/inch.
 6. There-usable carrier structure of claim 1 further comprising a coverremovably attached to said carrier frame for covering the at least onecarrying space.
 7. A re-usable carrier structure for releasably carryingone or more objects, said re-usable carrier comprising: a carrierstructure frame having a support member and adapted for receiving acover; a removable stretchable carrier base disposed on the supportmember of said carrier structure frame, wherein said removablestretchable carrier base is formed of a material that is stable attemperatures less than about 80° C. and is stretchable by about 10-100%or by over 30%; a removable tacky adhesive layer disposed on saidremovable stretchable carrier base for adhesively holding one or moreobjects, and a cover disposed on said carrier structure frame, whereinsaid cover is of an opaque material, wherein one or more objects adaptedto be carried on said removable tacky adhesive layer are released whensaid cover is removed and said removable stretchable carrier base isdeformed by an ejector, and said removable stretchable carrier base andremovable tacky adhesive layer thereon is removable from said carrierstructure without leaving a substantial residue so that said carrierstructure is available to be reused with another removable stretchablecarrier base.
 8. The re-usable carrier structure of claim 7 wherein thecarrier frame includes a waffle pack, a tray, a JEDEC tray, atape-and-reel, or a tape.
 9. The re-usable carrier structure of claim 7wherein said removable stretchable carrier base is stable to resistdeformation by heat at temperatures less than or equal to about 300° C.,or has anti-static properties, or is stable to resist deformation byheat at temperatures less than or equal to about 300° C. and hasanti-static properties.
 10. The re-usable carrier structure of claim 7wherein said removable stretchable carrier base is stable to resistdeformation by heat at temperatures less than or equal to about 150° C.,or has anti-static properties, or is stable to resist deformation byheat at temperatures less than or equal to about 150° C. and hasanti-static properties.
 11. The re-usable carrier structure of claim 7:wherein said removable stretchable carrier base defines sub-compartmentsand the tacky adhesive layer is disposed in the sub-compartments; orwherein said tacky adhesive layer has a peel strength of less than about50 grams/inch; or wherein said tacky adhesive layer has a peel strengthof about 20-2000 grams/inch; or wherein said removable stretchablecarrier base defines sub-compartments and the tacky adhesive layer isdisposed in the sub-compartments, and wherein said tacky adhesive layerhas a peel strength of less than about 50 grams/inch; or wherein saidremovable stretchable carrier base defines sub-compartments and thetacky adhesive layer is disposed in the sub-compartments, and whereinsaid tacky adhesive layer has a peel strength of about 20-2000grams/inch.
 12. The re-usable carrier structure of claim 7 furthercomprising a cover removably attached to said carrier frame for coveringthe at least one carrying space.
 13. A re-usable carrier for releasablycarrying one or more objects, said re-usable carrier comprising: acarrier structure having a support member defining at least one pocketwherein one or more objects can be carried, wherein said carrierstructure is adapted for receiving a cover; a removable stretchablecarrier base disposed on the support member in the at least one pocketof said carrier structure, wherein said removable stretchable carrierbase is formed of a material that is stable at temperatures less thanabout 80° C. and is stretchable by about 10-100% or by over 30%; and atacky adhesive layer disposed on said removable stretchable carrier basefor adhesively holding one or more objects; a cover disposed on saidcarrier structure, wherein said cover is of a material opaque toultraviolet radiation for blocking ultraviolet radiation from impingingupon said tacky adhesive layer, wherein said carrier structure includesa rectangular frame having a ledge providing the support member, andwherein said cover includes first and second covers disposed on oppositeends of said rectangular frame, wherein said first and second covers andsaid rectangular frame enclose said removable stretchable carrier base,whereby one or more objects carried on said adhesive layer are releasedwhen said cover is removed and said removable stretchable carrier baseand said adhesive layer are stretched by an ejector.
 14. The re-usablecarrier of claim 13 wherein the carrier frame includes a waffle pack, atray, a JEDEC tray, a tape-and-reel, or a tape.
 15. The re-usablecarrier of claim 13 wherein said removable stretchable carrier base isstable to resist deformation by heat at temperatures less than or equalto about 300° C., or has anti-static properties, or is stable to resistdeformation by heat at temperatures less than or equal to about 300° C.and has anti-static properties.
 16. The re-usable carrier of claim 13wherein said removable stretchable carrier base is stable to resistdeformation by heat at temperatures less than or equal to about 150° C.,or has anti-static properties, or is stable to resist deformation byheat at temperatures less than or equal to about 150° C. and hasanti-static properties.
 17. The re-usable carrier of claim 13: whereinsaid removable stretchable carrier base defines sub-compartments and thetacky adhesive layer is disposed in the sub-compartments; or whereinsaid tacky adhesive layer has a peel strength of less than about 50grams/inch; or wherein said tacky adhesive layer has a peel strength ofabout 20-2000 grams/inch; or wherein said removable stretchable carrierbase defines sub-compartments and the tacky adhesive layer is disposedin the sub-compartments, and wherein said tacky adhesive layer has apeel strength of less than about 50 grams/inch; or wherein saidremovable stretchable carrier base defines sub-compartments and thetacky adhesive layer is disposed in the sub-compartments, and whereinsaid tacky adhesive layer has a peel strength of about 20-2000grams/inch.
 18. The re-usable carrier of claim 13 further comprising acover removably attached to said carrier frame for covering the at leastone carrying space.
 19. A re-usable carrier structure for carrying anarticle, comprising: a carrier frame comprising a JEDEC tray or a wafflepack defining at least one carrying space; a removable carrier basedisposed in the at least one carrying space of said carrier frame, saidremovable carrier base defining sub-compartments; a tacky adhesivedisposed in the sub-compartments of said removable carrier base; whereinan article may be held by and carried on the tacky adhesive in asub-compartment of the removable carrier base of said carrier structure,and wherein the article is removable leaving said removable carrier baseand tacky adhesive thereon on said carrier frame, and wherein saidremovable carrier base is removable from said carrier frame so that saidcarrier frame is available to be reused with another removable carrierbase.
 20. The re-usable carrier structure of claim 19 wherein saidremovable carrier base is formed of a material that is stable attemperatures less than about 80° C. or less than about 150° C. or lessthan about 300° C., that has anti-static properties, that is stretchableby about 10-100% or by over 30%, or a combination of the foregoing.